In a head-mounted display (HMD), battery packs can be non-collocated. For example, to provide balance, a first battery pack could be located on the right side of an HMD and a second battery pack located on the left side of the HMD. This arrangement helps provide an equal amount of weight on both sides of the user's head. If the batteries, which are one of the heavier components in an HMD, are collocated on only one side of a device then the device may feel uncomfortable to the user. The different locations of the batteries mean the batteries can be exposed to different system conditions and environmental conditions that affect battery operation. These conditions can cause one battery or both batteries to age more quickly than they otherwise would.